It is readily possible to send a secure email message all be it somewhat complex. You need, as the sender an S/MIME compliant email software package and a copy of the recipient's public key.
In order to obtain the recipient's public key it is necessary for the recipient to enroll for a digital certificate. The enrollment process includes the creation of a public key and a private key, however care must be taken for the protection of the private key and trust must be established between the sender and the recipient's public key.
Trust leads to the need for a Certificate Authority, a mutually agreed entity that has been vetted and trusted by both parties by means of each party taking the additional step of installing the Certificate Authority's root certificate.
Additionally it is necessary to establish as to whether or not the recipient's public key has been stolen by means of checking a certificate revocation list, which first must be located and trusted. These requirements and others are called creating a Public Key Infrastructure (PKI) and necessitate the creation of security documentation called Certificate Policy (CP) and Certificate Practise Statement (CPS).
Despite S/Mime being readily available for many years there has been very little uptake of the method because of the high costs and skills required to roll out a PKI along with the need for some complex knowledge of public key encryption being required by both sender and recipient. In addition, the sender needs to make trust discussions as to the validity of the recipient's certificate which often leads to reading complex Certificate Policy documentation for each recipient copied on the email. This high cost and complexity along with problems distributing the recipient's public keys has prevented the adoption of the technology.
An additional problem linked with sending encrypted email message is namely that of content checking gateways. Such gateways usually require traversing in order to deliver the message successfully. These gateways are typically configured to check for viruses and sensitive words within the content of the message or attachment. In order for said gateway to achieve this check it is required that the gateway decrypts the message. This in turn requires that the gateway has access to the recipient's private key or that the gateway must be copied on the email which usually requires the sender to re-send and make trust decisions as to the validity of the gateway.
An alternative method employed by some systems is the sending of a program through email which, when opened by the recipient, prompts for a password and then automatically decrypts a message held within the program.
In recent time this last method has been shown to be unworkable because of email virus programs that employ the same method, namely that of assuming that the recipient will execute an attached program. The threat can be countered by content checking gateways or email programs which quarantine any attached executable programs and thus prevent their delivery.
A second alternative method is that of storing a message on an Internet facing web server and then delivering the message via the web server's secure communication link. This method has the draw back that the web server can be accessed by anyone, thus requiring a means of authenticating the recipient. The authentication can be achieved by means of the sender pre-agreeing a password with the recipient. The pre-agreed password requires a manual task on the part of the sender and fails to scale when sending high numbers of messages to multiple recipients.
The purpose of the present invention is to define a method and system whereby a recipient can read a secure message without the need for any additional software, any public keys or any complex encryption knowledge, the recipient only requiring standard email software, a web browser and a device capable of receiving their authentication code, for example, a mobile phone. In addition the method and system of the present invention provides a message capable of traversing any content checking email gateways and does not require the sender to take any additional manual tasks.
According to a first aspect, the present invention consists in a method for secure electronic communication of an email message from an originator to a recipient, said method comprising the steps of: said originator removing at least a portion of the content of the message; said originator employing first communication means to send the removed portion to an external store, said external store being operative to grant access to said stored removed portion upon presentation of an authentication code; said originator employing email to send the residue of the message, with notification that said removed portion is in said store, to said recipient; employing second communications means to send said authentication code to said recipient; said recipient accessing said external store; and said recipient employing third communication means to provide said external store with said authentication code for said external store to grant access to said removed portion.
According to a second aspect, the present invention consists in a system for secure electronic communication of an email message from an originator to a recipient, said system comprising: removal means for said originator to remove at least a portion of the content of the message; first communication means for said originator to send the removed portion to an external store, said external store being operative to grant access to said stored removed portion upon presentation of an authentication code; email means for said originator to send the residue of the message, with notification that said removed portion is in said store, to said recipient; second communications means for to send said authentication code to said recipient; accessing means for said recipient to access said external store; and third communication means for said recipient to provide said external store with said authentication code for said external store to grant access to said removed portion.
The invention further provides notification means for the store to send a notification message to the originator when the recipient has gained access to the removed portion.
The invention further provides that the store can be operative to generate at least a portion of the authentication code.
The invention further provides that the first communication means can include a secure Internet connection, that the secure Internet connection can employ encryption, and that the secure Internet connection can include the use of a Secure Socket Layer (SSL).
The invention further provides that the first communication means can comprise a secure network and that the secure network can include the use of encryption.
The invention further provides that the second communication means can include means to connect through a communications gateway, that the gateway can be a cellular telephone network, the invention including means to send the authentication code to the recipient as a visually readable message which can be a short message service text message or can include Unstructured Supplementary Service Data (USSD).
The invention further provides that the gateway can connect to a Microsoft Passport network and that the second communication means can send the authentication code via the recipient's passport.
The invention further provides that the gateway can connect to a Microsoft Messenger network and the second communication means can send the authentication code as an instant message.
The invention further provides that the gateway can connect to a pager network and that the second communication means can send the authentication code as a pager message.
The invention further provides that the gateway can connect to a voice network and that the second communication means can include means to generate the authentication code as a synthesised voice message.
The invention further provides that the authentication code can be uniquely generated for each stored portion.
The invention further provides for the inclusion of means to provide the identity of the originator along with the authentication code.
The invention further provides that the third means of communication can include a secure Internet connection from a web browser connecting via an encrypted link to a web server.
The invention further provides that the third means of communication can include a secure Internet connection from a web browser connecting via the URL HTTPS.
The invention further provides that the third means of communication can include a secure Internet connection from a web browser connecting via a Secure Socket layer (SSL) to a web server.
The invention further provides that the third means of communication can include a secure Internet connection from a web browser connecting via Transport Layer Security (TLS) to a web server.
The invention further provides that the third means of communication can include a secure Internet connection from a mobile device's Wireless Access Protocol (WAP) browser connecting to a WAP gateway.